Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, open-world and non-destructive. Beyond that the description discloses substantive content traits: USD estimates, cash-vs-credits distinction, and eligibility traps (students-only, region-locked, in-person, approval) plus duplicate-listing flagging, which tells the agent what terrain to expect.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single dense sentence, front-loaded with the purpose before the field list and accepted inputs. The enumerations of fields are long but each carries informational weight, so there is little waste.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, so the description carries the burden of describing what comes back, and it does so thoroughly (brief, prize breakdown, deadline, timestamps, apply link, eligibility, duplicates). Nothing an agent needs to invoke or interpret this tool seems missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the schema already documents 'ref' with URL/id/title examples. The description restates the same accepted forms without adding syntax or ambiguity-resolution rules, so baseline 3 is correct.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Full details for one HackList listing') and the single-listing scope distinguishes it from siblings like search, search_opportunities, and best_opportunities. An agent knows this is the detail-lookup path for one known item.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It implies usage by noting the accepted reference forms (URL, id, title), but never says when to choose this over search/fetch or what to do if the reference is ambiguous. Usage is inferable rather than explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.